If you're looking for manga similar to Servamp: Hai ni Mamireta Shoukei - All the world's a stage, you might like these titles.
The Quincies' Thousand Year Blood War is over, but the embers of turmoil still smolder in the Soul Society. Tokinada Tsunayashiro, elevated to head of his clan after a slew of assassinations take out every other claimant to the title, has a grand plan to create a new Soul King. His dark ambitions soon sow the seeds of a new total war across the realms, but all is not lost. There is one unlikely Soul Reaper who holds the key to defusing the conflict—Shuhei Hisagi, Assistant Captain of the Ninth Company and reporter for the Seireitei Bulletin!
Eiji is a high schooler living with his father - a novelist who can't sell his works. Eiji is rather anti-social, nerdy, and worst of all, poor. But he is a kind, honest young man who never forgets how his deceased mother taught him to be compassionate towards others. He (along with everyone else) deeply admires his classmate Aoi-san, the daughter of the president of a large corporation. But Eiji had never been able to face her due to the enormous difference in their social standings. One day after school, he returns home to find that Aoi had come to visit him, and there, she says a few words that astonish him even more than he already is...
When I came down with a cold and was bedridden, a beautiful woman wearing cat ears appeared before me. But it turns out that she was actually my pet cat...?! She's usually calm, cool, and collected, but put cat ears on her and she's fawning all over me. How will my love with this mysterious beautiful woman turn out?